PROSPECT-I Measurement of Absolute Reactor Antineutrino Flux

The Precision Reactor Oscillation and SPECTrum (PROSPECT) experiment is a short-baseline reactor experiment designed to measure the spectrum of antineutrinos and search for evidence of short baseline sterile neutrino oscillations. From 2018 to 2019, the first-generation detector, PROSPECT-I, took data while located roughly 7 m from the 85 MW, compact, highly-enriched High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). PROSPECT-I has demonstrated the highest signal-to-background ratio of any surface antineutrino detector with minimal overburden, placing stringent limits on eV scale sterile neutrino oscillations, setting new direct limits on boosted dark matter models, and providing the world’s most precise ²³⁵U antineutrino spectrum. This talk will outline the ongoing work by the PROSPECT collaboration on measuring the neutron capture ratio in the detector, aiming towards making an absolute flux measurement of the reactor antineutrinos.